Patent Literature 1 describes that, in a monitor apparatus with an input unit in a production and assembly system, a display-switching-security control unit reads out screen data, in which a security setting value is described and set for each of display parts, reads out a device value (a security level value) set in a programmable controller (PC), compares the security level value and the security setting value, and performs, based on a comparison result, a switching instruction for display/non-display of the display parts for each of the display parts. Consequently, according to Patent Literature 1, when the screen data is displayed, display/non-display of the display parts is performed for each of the display parts based on the comparison result. Therefore, it is possible to display only necessary characters and numerical values on the screen in one image data only through security setting.
Patent Literature 2 describes that, in a monitoring control apparatus that performs monitoring control on a plurality of apparatuses that are subject to monitoring control, an operation-execution-right-determination processing unit receives an input operator name and an input password, retrieves, based on the operator name and the password, an operator group, to which an operator belongs, from a person-in-charge group table, further retrieves a function group, an execution right for which is permitted to the operator group, from a security table A, stores a retrieval result on a memory as execution propriety information, retrieves an apparatus group, an execution right of which is permitted to the operator group, from a security group B, and stores a retrieval result on the memory as execution propriety information. Consequently, according to Patent Literature 2, propriety of execution by the operator is discriminated with reference to the execution propriety information stored in the memory. Therefore, it is possible to give flexibility to configuration contents of a security function.
Patent Literature 3 describes that, in a programmable display, a key-information control unit recognizes connection of a hardware key, in which information concerning an operator is stored, to the programmable display and a CPU acquires the information concerning the operator from the hardware key, compares the information concerning the operator with list information stored in a key-list storing unit, and, when the information concerning the operator is included in the list information, instructs a graphic controller to perform display control. Consequently, according to Patent Literature 3, it is possible to control a display operation of a display screen corresponding to the operator by connecting the hardware key. Therefore, it is unnecessary to apply access control by a password input as in the conventional technology. Thus, a situation such as a leakage of passwords does not occur.